1. Technical Field
The present invention embodiments pertain to Geographic Information Systems (GIS). In particular, the present invention embodiments pertain to a geographic overlay system that provides a detailed geographical and data profile of a local setting.
2. Discussion of the Related Art
Internet (or web) Geographic Information Systems (GIS) typically comprise a GIS database that resides on a server, a user interface on the client-side and some type of active server page that processes requests between a browser and the server. In addition, some of these systems have an administration interface to assist a System Administrator in automatically generating the web protocols for displaying the GIS database in a client browser. There are a variety of approaches for implementing web GIS. For example, a server-based Internet Map Server (IMS) web GIS system dynamically produces opaque tiled raster images on the server-side that must be uploaded to the user browser (e.g., tiles are portions of an image that are arranged or assembled to form the overall image). These raster-based images may employ various file formats (e.g., JPEG, GIF, PNG or MWF formats). A main problem with these types of systems includes requiring a delay in request processing time in order to upload the images.
Adobe Flash-based mapping systems (which may or may not have a Flash-based interface and are not connected to a database) upload static SWF files stored on a server, either on a per-request basis or upon launch of a web site. Problems related to these types of Flash mapping systems include the limited breadth of the geographic area covered and the delay in processing time required for uploading the SWF files to the client browser.
Flash mapping type systems are connected to a server that dynamically generates SWF files on the server-side as needed based on user input. These SWF files are uploaded to a user browser and arranged as tiles. A main problem with these types of systems includes requiring a delay in request processing time in order upload the SWF files.
AJAX-based (Asynchronous JavaScript and XML) client-side API web mapping systems use a combination of server-based tiling of raster images with client-side JavaScript to dynamically render vector-based points within the client browser. A main problem of these types of systems includes the limited amount of client-side rendering performed due to client-side memory restrictions and data transfer limitations. Accordingly, these types of systems cannot dynamically render interactive polygons (e.g., defining or representing a geographic area on the map). Rather, the systems are limited to rendering points (e.g., representing specific locations or points of interest on a map) and lines (e.g., representing streets on a map), simple datasets and functions.
SVG (Scalable Vector Graphics) vector-based web GIS systems suffer from the disadvantage of requiring a non-standard “plug-in” download in order to use the system.